In recent years, a portable network terminal having an information processing function such as a tablet type computer, a smart phone or the like spreads rapidly. In many cases, a touch screen (a touch panel) having an input device and a display device integrated with each other is used for inputting/outputting information to these terminals. The input to the touch screen is carried out by touching the screen, and a touch pen or a finger is mainly used as means for carrying out the input to the screen.
The input using the touch pen has an advantage that it is suitable for inputting small characters or performing a fine button operation or the like, and has a disadvantage that the touch pen should be carried. The input using one of fingers is not suitable for the input of small characters or the fine button operation but has an advantage that an operation can be performed intuitively and the touch pen does not need to be carried.
There is disclosed the invention related to an input device capable of performing input with a touch pen or a finger and identifying whether input means is the touch pen or the finger in order to make use of both characteristics (for example, see Patent Document 1). Moreover, there are disclosed the invention for changing an arrangement or a size of an operating button depending on whether the input means is the touch pen or the finger (for example, see Patent Document 2) and the invention for executing different functions depending on the input means such as input of information with the touch pen or page scroll with the finger (for example, see Patent Documents 3 and 4).